Anal Cancer Prevention (PDQ®)–Patient Version

What is prevention?

Cancerprevention is action taken to lower the chance of getting
cancer. By preventing cancer, the number of new cases of cancer
in a group or population is lowered. Hopefully, this will lower
the number of deaths caused by cancer.

To prevent new cancers from starting, scientists look at risk
factors and protective factors. Anything that increases your
chance of developing cancer is called a cancer risk factor;
anything that decreases your chance of developing cancer is
called a cancer protective factor.

Some risk factors for cancer can be avoided, but many cannot.
For example, both smoking and inheriting certain genes are
risk factors for some types of cancer, but only smoking can be
avoided. Regular exercise and a healthy diet may be protective
factors for some types of cancer. Avoiding risk factors and
increasing protective factors may lower your risk but it does
not mean that you will not get cancer.

General Information About Anal Cancer

Key Points

Anal cancer is a disease in which malignant (cancer) cells
form in the tissues of the anus.

Squamous cell carcinoma is the most common type of anal cancer.

In the United States, the number of new cases of anal cancer has increased in recent years.

Anal cancer is a disease in which malignant (cancer) cells
form in the tissues of the anus.

The anus is the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. The anus is formed partly from the outer skin layers of the body and partly from the intestine. Two ring-like muscles, called sphincter muscles, open and close the anal opening and let stool pass out of the body. The anal canal, the part of the anus between the rectum and the anal opening, is about 1-1½ inches long. Enlarge

Anatomy of the lower digestive system, showing the colon and other organs.

The skin around the outside of the anus is called the perianal area. Tumors in this area are skin tumors, not anal cancer.

Squamous cell carcinoma is the most common type of anal cancer.

Another type of anal cancer, called anal adenocarcinoma, is very rare and is not discussed in this summary.

In the United States, the number of new cases of anal cancer has increased in recent years.

From 2001 to 2010, new cases of anal cancer and deaths from anal cancer increased each year. The increase in new cases was slightly higher in women and the increase in deaths from anal cancer was slightly higher in men.

Avoiding cancerrisk factors may help prevent certain cancers. Risk factors include smoking, being overweight, and not getting enough exercise. Increasing protective factors such as quitting smoking and exercising may also help prevent some cancers. Talk to your doctor or other health care professional about how you might lower your risk of cancer.

The risk of anal cancer is higher in men who are HIV-positive and have sex with men compared with men who are HIV-negative and have sex with men. Women who are HIV-positive also have an increased risk of anal cancer compared with women who are HIV-negative.

Studies show that intravenousdrug use or cigarette smoking may further increase the risk of anal cancer in patients who are HIV-positive.

Immunosuppression

Immunosuppression is a condition that weakens the body's immune system and its ability to fight infections and other diseases. Chronic (long-term) immunosuppression may increase the risk of anal cancer because it lowers the body's ability to fight HPV infection.

Having an autoimmune disorder such as Crohn disease or psoriasis may increase the risk of anal cancer. It is not clear if the increased risk is due to the autoimmune condition, the treatment for the condition, or a combination of both.

Certain sexual practices

The following sexual practices increase the risk of anal cancer because they increase the chance of being infected with HPV:

Having receptive anal intercourse (anal sex).

Having many sexual partners.

Sex between men.

Men and women who have a history of anal warts or other sexually transmitted diseases also have an increased risk of anal cancer.

Cigarette smoking

Studies show that cigarette smoking increases the risk of anal cancer. Studies also show that current smokers have a higher risk of anal cancer than smokers who have quit or people who have never smoked.

The following protective factor decreases the risk of anal cancer:

HPV vaccine

The human papillomavirus (HPV) vaccine is used to prevent anal cancer, cervical cancer, vulvar cancer, and vaginal cancer caused by HPV. It is also used to prevent lesions caused by HPV that may become cancer in the future.

Studies show that being vaccinated against HPV lowers the risk of anal cancer. The vaccine may work best when it is given before a person is exposed to HPV.

It is not clear if the following protective factor decreases the risk of anal cancer:

Condom use

It is not known if the use of condoms protects against anal HPV infection. This is because not enough studies have been done to prove this.

Cancer prevention clinical trials are used to study ways
to prevent cancer.

Cancer preventionclinical trials are used to study ways to
lower the risk of developing certain types of cancer. Some
cancer prevention trials are conducted with healthy people who
have not had cancer but who have an increased risk for cancer.
Other prevention trials are conducted with people who have had
cancer and are trying to prevent another cancer of the same type
or to lower their chance of developing a new type of cancer.
Other trials are done with healthy volunteers who are not known
to have any risk factors for cancer.

The purpose of some cancer prevention clinical trials is to
find out whether actions people take can prevent cancer. These
may include eating fruits and vegetables, exercising, quitting
smoking, or taking certain medicines, vitamins, minerals, or
food supplements.

New ways to prevent anal cancer are being studied in clinical
trials.

Clinical trials are taking place in many parts of the country.
Information about clinical trials for anal cancer prevention can be found in the Clinical
Trials section of the
NCI Web
site.

About This PDQ Summary

About PDQ

Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.

PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.

Purpose of This Summary

This PDQ cancer information summary has current information about anal cancer prevention. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.

Reviewers and Updates

Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Date Last Modified") is the date of the most recent change.

Clinical Trial Information

A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Clinical trials are listed in PDQ and can be found online at NCI's website. Many cancer doctors who take part in clinical trials are also listed in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER (1-800-422-6237).

Permission to Use This Summary

PDQ is a registered trademark. The content of PDQ documents can be used freely as text. It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. However, a user would be allowed to write a sentence such as “NCI’s PDQ cancer information summary about breast cancer prevention states the risks in the following way: [include excerpt from the summary].”

Images in this summary are used with permission of the author(s), artist, and/or publisher for use in the PDQ summaries only. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner. It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 2,000 scientific images.

Disclaimer

The information in these summaries should not be used to make decisions about insurance reimbursement. More information on insurance coverage is available on Cancer.gov on the Managing Cancer Care page.

Contact Us

More information about contacting us or receiving help with the Cancer.gov website can be found on our Contact Us for Help page. Questions can also be submitted to Cancer.gov through the website’s E-mail Us.

Updated: December
11, 2014

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